<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>css常用值</title>
  <link rel="stylesheet" href="">
  <style>
    h1 {
      color: red;
      color: rgb(100,100,100);
      color: rgb(0,0,0);
      color: rgb(255,0,0);
      color: rgb(0,0,255);
      color: rgb(90,33,33);
      color: #ff0000;
      color: #0f0;
      color: #000000;
      color: rgba(255,0,0,0.5);
      color: rgba(255,0,0,.7);
      color: rgba(255,0,0,0);
    }
    .d1 {
        width: 450px;
        height: 300px;
        background-color: red;
        background-image: url("img/mr.png");
        background-size: 150px 300px;
    }
    .d2 {
        width: 500px;
        height: 300px;
        background-image: linear-gradient(45deg,red,rgb(0,255,0),#00f,rgba(0,0,255,0.3));
    }
    .d3 {
        width: 500px;
        height: 300px;
        border: 5px red solid;
        background-image: url("day02/img/mr.png");
        background-repeat: no-repeat;
        background-position:center ;
        background-position: left bottom;
        background-position: 0 50%;
    }

  </style>
</head>
<body>
    <h1>

    </h1>
    <div class="d1"></div>
    <div class="d2"></div>
    <div class="d3"></div>

</body>
</html>